1. Field of the Invention
The present invention relates to a method for determining and monitoring ageing of blood bags in blood transfusion units and healthcare units.
2. Discussion of Background Information
Blood bags are currently obtained from blood transfusion units and each bag is dated at the time of donation. The dating marks the start of the life of the bag and of the derived products and the life represents a useful life of the blood and lasts a predetermined time. The donated blood bags are subjected to filtering, centrifugation, and separation. The end result of which is, in particular, a derived product consisting of a bag of red blood cells which is intended to be transfused. The predetermined life of the bag of red blood cells is forty-five days starting from when the blood was donated. The bags of red blood cells are stored in the blood transfusion units and delivered as and when they are required by healthcare units. It is possible that bags of red blood cells which had been intended for dealing with an incident during an operation may not have been used. Since it is currently impossible to have a reliable guarantee of the quality of the content of the bag of red blood cells, with a view to its being used another time, it will be destroyed. Because destruction of the unused bags of red blood cells currently represents wastage of about twelve percent of all the donated blood bags, it is imperative that this should be reduced.
Since the bags of red blood cells are currently transported between the blood transfusion unit and the healthcare unit without particular precautions, a study is underway with a transportation company with a view to guaranteeing continuity of the cold chain between these two units. In this regard, the blood bag is accordingly placed in a refrigerated container, inside which there is a device indicating the temperature in the container throughout transport. By virtue of being placed in a suitable refrigerator at the healthcare unit when they arrive, the bags of red blood cells can be returned to the blood transfusion unit if they have not yet been taken out in order to be made available to a surgeon.
When blood is donated, the blood is transferred into a parent blood bag connected to a filter, which is itself connected to a primary blood bag. The primary blood bag is combined with a group of three secondary bags, to which it is connected through flexible tubes arranged in parallel. The blood from the parent blood bag is filtered and introduced into the primary blood bag. The primary blood bag is centrifuged in order to separate the red blood cells, platelets and plasma, which are then respectively transferred into each of the three bags, and it is the bag containing the red blood cells which is used to carry out blood transfusions. As a reminder, the platelets are isolated only when there is a significant need. Otherwise, they are left with the red blood cells and only two secondary bags are used.
A device for tracking blood bags according to Patent Application FR-9804802 is under development. This device assigns an electronic chip to the blood bag. Each electronic chip has a ring antenna which communicates with the ring antenna of an electronic communication device, which is connected to a computing device and is capable of supplying the electronic chip with energy and with information which it stores and which it can return to the computing device via an electronic communication device. A parent electronic chip is fixed on the parent blood bag and gathers all the information about the donor and the results of the analyses for qualifying the parent blood bag. The parent electronic chip is fixed on a flexible chip support of rectangular shape with a side length measuring a few centimeters, on which a metallized circuit is printed in loops forming the ring antenna for communication. In one aspect of the invention, the flexible chip support of the primary electronic chip is placed on one of the large faces of the parent blood bag, underneath a rectangular label covering the majority of a main face. The parent chip supports are preferably always placed at the same location with respect to the label, so as to facilitate positioning of the antenna of the electronic communication device. A Patent Application FR-9908887 describes an agitating balance provided with an electronic communication device for recording the characteristics of the blood donor and the donation conditions in the parent electronic chip of the parent blood bag. The blood from the parent blood bag is transferred into the primary blood bag by filtration. The primary blood bag has a primary electronic chip, into which the information contained in the parent electronic chip is transferred, together with the information relating to the filtration conditions. The primary blood bag is then centrifuged. The constituents are separated and are introduced into the secondary blood bags. The secondary blood bags are equipped with secondary electronic chips, which are identical to the parent and primary electronic chips and are fixed on a flexible chip support placed underneath a label covering one face of the secondary blood bag, and preferably at a location such that when the parent, primary and secondary blood bags are stacked, the parent and primary electronic chip supports do not cover one another and do not cover the secondary flexible chip supports. The secondary electronic chips of the secondary bags, that is to say the bag of red blood cells, the bag of plasma and optionally the bag of platelets, are updated by transferring information from the primary electronic chip of the primary blood bag, supplemented with information relating to the parameters used for separating the blood components. In regard to the bag of red blood cells that has been used for a blood transfusion, the secondary electronic chip which is associated with it contains the information relating to the conditions of its use and, in particular, the identity of the transfused patient.